The first message that arrives at the Receive port creates a
new instance of the Orchestration. All other messages would use the same
Orchestration for processing.
A BizTalk Correlation would ensure that the messages which
arrive into the Orchestration have at least one similar property. For example,
the messages arrive from the same Receive Port or they have the same InstanceID
or flag property. For a single Orchestration to exist, all the messages which
arrive at the orchestration must have one common property. This common property
of the messages must be encapsulated into a Correlation set.
The Correlation set created above shall be initialized on the receipt of the first message which
creates the Singleton Orchestration, all other subsequent messages would use
the same Correlation set and, therefore, the same Orchestration instance.
Figure 1 – Receive Shape
Properties Dialog box